Storage unit (SU) operative within non-disruptive and performant migration

ABSTRACT

A computing device includes an interface configured to interface and communicate with a dispersed storage network (DSN), a memory that stores operational instructions, and a processing module operably coupled to the interface and memory such that the processing module, when operable within the computing device based on the operational instructions, is configured to perform various operations. The computing device determines to facilitate migration of encoded data slices (EDSs) from a first storage unit (SU) pool to a second SU pool and identifies storage resources associated with the EDSs to be migrated. The computing device then generates a migration schedule for the EDSs based on performance information associated with storage resources and facilitates the migration of the plurality of EDSs based on the migration schedule using the storage resources based on an aggression factor and adapts the aggression factor as deemed necessary based on the performance information.

CROSS REFERENCE TO RELATED PATENTS

The present U.S. Utility Patent Application claims priority pursuant to 35 U.S.C. § 120 as a continuation of U.S. Utility patent application Ser. No. 15/974,345, entitled “SCHEDULING MIGRATION RELATED TRAFFIC TO BE NON-DISRUPTIVE AND PERFORMANT,” filed May 8, 2018, which is a continuation of U.S. Utility patent application Ser. No. 15/445,056, entitled “SCHEDULING MIGRATION RELATED TRAFFIC TO BE NON-DISRUPTIVE AND PERFORMANT,” filed Feb. 28, 2017, issued on Jul. 24, 2018 as U.S. Pat. No. 10,031,669, which claims priority pursuant to 35 U.S.C. § 120, as a continuation-in-part (CIP) of U.S. Utility patent application Ser. No. 15/056,517, entitled “SELECTING STORAGE UNITS IN A DISPERSED STORAGE NETWORK,” filed Feb. 29, 2016, issued on Aug. 8, 2017 as U.S. Pat. No. 9,727,266, which claims priority pursuant to 35 U.S.C. § 119(e) to U.S. Provisional Application No. 62/154,867, entitled “AUTHORIZING A SLICE ACCESS REQUEST IN A DISPERSED STORAGE NETWORK,” filed Apr. 30, 2015.

The U.S. Utility patent application Ser. No. 15/056,517 also claims priority pursuant to 35 U.S.C. § 120 as a continuation-in-part (CIP) of U.S. Utility patent application Ser. No. 12/903,212, entitled “DIGITAL CONTENT RETRIEVAL UTILIZING DISPERSED STORAGE,” filed 10-13-2010, issued on Oct. 4, 2016 as U.S. Pat. No. 9,462,316, which claims priority pursuant to 35 U.S.C. § 119(e) to U.S. Provisional Application No. 61/290,632, entitled “DIGITAL CONTENT DISTRIBUTED STORAGE,” filed Dec. 29, 2009, all of which are hereby incorporated herein by reference in their entirety and made part of the present U.S. Utility Patent Application for all purposes.

STATEMENT REGARDING FEDERALLY SPONSORED RESEARCH OR DEVELOPMENT

Not applicable.

INCORPORATION-BY-REFERENCE OF MATERIAL SUBMITTED ON A COMPACT DISC

Not applicable.

BACKGROUND OF THE INVENTION Technical Field of the Invention

This invention relates generally to computer networks and more particularly to dispersing error encoded data.

Description of Related Art

Computing devices are known to communicate data, process data, and/or store data. Such computing devices range from wireless smart phones, laptops, tablets, personal computers (PC), work stations, and video game devices, to data centers that support millions of web searches, stock trades, or on-line purchases every day. In general, a computing device includes a central processing unit (CPU), a memory system, user input/output interfaces, peripheral device interfaces, and an interconnecting bus structure.

As is further known, a computer may effectively extend its CPU by using “cloud computing” to perform one or more computing functions (e.g., a service, an application, an algorithm, an arithmetic logic function, etc.) on behalf of the computer. Further, for large services, applications, and/or functions, cloud computing may be performed by multiple cloud computing resources in a distributed manner to improve the response time for completion of the service, application, and/or function. For example, Hadoop is an open source software framework that supports distributed applications enabling application execution by thousands of computers.

In addition to cloud computing, a computer may use “cloud storage” as part of its memory system. As is known, cloud storage enables a user, via its computer, to store files, applications, etc. on an Internet storage system. The Internet storage system may include a RAID (redundant array of independent disks) system and/or a dispersed storage system that uses an error correction scheme to encode data for storage.

Data storage systems may operate from time to time to move information from one place to another therein. Unfortunately, prior art data storage systems cannot adequately perform such operations without sometimes deleteriously affecting other operations within such prior art data storage systems. There continues to be room for improvement in the operation of prior art data storage systems including the manner by which information is moved from one place to another therein.

BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWING(S)

FIG. 1 is a schematic block diagram of an embodiment of a dispersed or distributed storage network (DSN) in accordance with the present invention;

FIG. 2 is a schematic block diagram of an embodiment of a computing core in accordance with the present invention;

FIG. 3 is a schematic block diagram of an example of dispersed storage error encoding of data in accordance with the present invention;

FIG. 4 is a schematic block diagram of a generic example of an error encoding function in accordance with the present invention;

FIG. 5 is a schematic block diagram of a specific example of an error encoding function in accordance with the present invention;

FIG. 6 is a schematic block diagram of an example of a slice name of an encoded data slice (EDS) in accordance with the present invention;

FIG. 7 is a schematic block diagram of an example of dispersed storage error decoding of data in accordance with the present invention;

FIG. 8 is a schematic block diagram of a generic example of an error decoding function in accordance with the present invention;

FIG. 9 is a schematic block diagram of an embodiment of a Decentralized, or Distributed, Agreement Protocol (DAP) in accordance with the present invention;

FIG. 10 is a schematic block diagram of an example of creating pluralities of sets of slices in accordance with the present invention;

FIG. 11 is a schematic block diagram of an example of storage vaults in accordance with the present invention;

FIG. 12 is a schematic block diagram of an example of storing pluralities of sets of slices in accordance with the present invention;

FIG. 13 is a schematic block diagram of an example of adding a storage pool to the DSN in accordance with the present invention;

FIG. 14 is a schematic block diagram of an embodiment of a decentralized, or distributed, agreement protocol (DAP) for generating identified set of storage units in accordance with the present invention;

FIG. 15 is a schematic block diagram of another embodiment of a dispersed or distributed storage network (DSN) in accordance with the present invention;

FIG. 16 is a flowchart illustrating an example of pacing migration of encoded data slices (EDSs) in accordance with the present invention; and

FIG. 17 is a diagram illustrating an embodiment of a method for execution by one or more computing devices in accordance with the present invention.

DETAILED DESCRIPTION OF THE INVENTION

FIG. 1 is a schematic block diagram of an embodiment of a dispersed, or distributed, storage network (DSN) 10 that includes a plurality of computing devices 12-16, a managing unit 18, an integrity processing unit 20, and a DSN memory 22. The components of the DSN 10 are coupled to a network 24, which may include one or more wireless and/or wire lined communication systems; one or more non-public intranet systems and/or public internet systems; and/or one or more local area networks (LAN) and/or wide area networks (WAN).

The DSN memory 22 includes a plurality of storage units 36 that may be located at geographically different sites (e.g., one in Chicago, one in Milwaukee, etc.), at a common site, or a combination thereof. For example, if the DSN memory 22 includes eight storage units 36, each storage unit is located at a different site. As another example, if the DSN memory 22 includes eight storage units 36, all eight storage units are located at the same site. As yet another example, if the DSN memory 22 includes eight storage units 36, a first pair of storage units are at a first common site, a second pair of storage units are at a second common site, a third pair of storage units are at a third common site, and a fourth pair of storage units are at a fourth common site. Note that a DSN memory 22 may include more or less than eight storage units 36. Further note that each storage unit 36 includes a computing core (as shown in FIG. 2, or components thereof) and a plurality of memory devices for storing dispersed error encoded data.

Each of the computing devices 12-16, the managing unit 18, and the integrity processing unit 20 include a computing core 26, which includes network interfaces 30-33. Computing devices 12-16 may each be a portable computing device and/or a fixed computing device. A portable computing device may be a social networking device, a gaming device, a cell phone, a smart phone, a digital assistant, a digital music player, a digital video player, a laptop computer, a handheld computer, a tablet, a video game controller, and/or any other portable device that includes a computing core. A fixed computing device may be a computer (PC), a computer server, a cable set-top box, a satellite receiver, a television set, a printer, a fax machine, home entertainment equipment, a video game console, and/or any type of home or office computing equipment. Note that each of the managing unit 18 and the integrity processing unit 20 may be separate computing devices, may be a common computing device, and/or may be integrated into one or more of the computing devices 12-16 and/or into one or more of the storage units 36.

Each interface 30, 32, and 33 includes software and hardware to support one or more communication links via the network 24 indirectly and/or directly. For example, interface 30 supports a communication link (e.g., wired, wireless, direct, via a LAN, via the network 24, etc.) between computing devices 14 and 16. As another example, interface 32 supports communication links (e.g., a wired connection, a wireless connection, a LAN connection, and/or any other type of connection to/from the network 24) between computing devices 12 & 16 and the DSN memory 22. As yet another example, interface 33 supports a communication link for each of the managing unit 18 and the integrity processing unit 20 to the network 24.

Computing devices 12 and 16 include a dispersed storage (DS) client module 34, which enables the computing device to dispersed storage error encode and decode data as subsequently described with reference to one or more of FIGS. 3-8. In this example embodiment, computing device 16 functions as a dispersed storage processing agent for computing device 14. In this role, computing device 16 dispersed storage error encodes and decodes data on behalf of computing device 14. With the use of dispersed storage error encoding and decoding, the DSN 10 is tolerant of a significant number of storage unit failures (the number of failures is based on parameters of the dispersed storage error encoding function) without loss of data and without the need for a redundant or backup copies of the data. Further, the DSN 10 stores data for an indefinite period of time without data loss and in a secure manner (e.g., the system is very resistant to unauthorized attempts at accessing the data).

In operation, the managing unit 18 performs DS management services. For example, the managing unit 18 establishes distributed data storage parameters (e.g., vault creation, distributed storage parameters, security parameters, billing information, user profile information, etc.) for computing devices 12-14 individually or as part of a group of user devices. As a specific example, the managing unit 18 coordinates creation of a vault (e.g., a virtual memory block associated with a portion of an overall namespace of the DSN) within the DSN memory 22 for a user device, a group of devices, or for public access and establishes per vault dispersed storage (DS) error encoding parameters for a vault. The managing unit 18 facilitates storage of DS error encoding parameters for each vault by updating registry information of the DSN 10, where the registry information may be stored in the DSN memory 22, a computing device 12-16, the managing unit 18, and/or the integrity processing unit 20.

The DSN managing unit 18 creates and stores user profile information (e.g., an access control list (ACL)) in local memory and/or within memory of the DSN module 22. The user profile information includes authentication information, permissions, and/or the security parameters. The security parameters may include encryption/decryption scheme, one or more encryption keys, key generation scheme, and/or data encoding/decoding scheme.

The DSN managing unit 18 creates billing information for a particular user, a user group, a vault access, public vault access, etc. For instance, the DSN managing unit 18 tracks the number of times a user accesses a non-public vault and/or public vaults, which can be used to generate a per-access billing information. In another instance, the DSN managing unit 18 tracks the amount of data stored and/or retrieved by a user device and/or a user group, which can be used to generate a per-data-amount billing information.

As another example, the managing unit 18 performs network operations, network administration, and/or network maintenance. Network operations includes authenticating user data allocation requests (e.g., read and/or write requests), managing creation of vaults, establishing authentication credentials for user devices, adding/deleting components (e.g., user devices, storage units, and/or computing devices with a DS client module 34) to/from the DSN 10, and/or establishing authentication credentials for the storage units 36. Network administration includes monitoring devices and/or units for failures, maintaining vault information, determining device and/or unit activation status, determining device and/or unit loading, and/or determining any other system level operation that affects the performance level of the DSN 10. Network maintenance includes facilitating replacing, upgrading, repairing, and/or expanding a device and/or unit of the DSN 10.

The integrity processing unit 20 performs rebuilding of ‘bad’ or missing encoded data slices. At a high level, the integrity processing unit 20 performs rebuilding by periodically attempting to retrieve/list encoded data slices, and/or slice names of the encoded data slices, from the DSN memory 22. For retrieved encoded slices, they are checked for errors due to data corruption, outdated version, etc. If a slice includes an error, it is flagged as a ‘bad’ slice. For encoded data slices that were not received and/or not listed, they are flagged as missing slices. Bad and/or missing slices are subsequently rebuilt using other retrieved encoded data slices that are deemed to be good slices to produce rebuilt slices. The rebuilt slices are stored in the DSN memory 22.

FIG. 2 is a schematic block diagram of an embodiment of a computing core 26 that includes a processing module 50, a memory controller 52, main memory 54, a video graphics processing unit 55, an input/output (IO) controller 56, a peripheral component interconnect (PCI) interface 58, an IO interface module 60, at least one IO device interface module 62, a read only memory (ROM) basic input output system (BIOS) 64, and one or more memory interface modules. The one or more memory interface module(s) includes one or more of a universal serial bus (USB) interface module 66, a host bus adapter (HBA) interface module 68, a network interface module 70, a flash interface module 72, a hard drive interface module 74, and a DSN interface module 76.

The DSN interface module 76 functions to mimic a conventional operating system (OS) file system interface (e.g., network file system (NFS), flash file system (FFS), disk file system (DFS), file transfer protocol (FTP), web-based distributed authoring and versioning (WebDAV), etc.) and/or a block memory interface (e.g., small computer system interface (SCSI), internet small computer system interface (iSCSI), etc.). The DSN interface module 76 and/or the network interface module 70 may function as one or more of the interface 30-33 of FIG. 1. Note that the IO device interface module 62 and/or the memory interface modules 66-76 may be collectively or individually referred to as IO ports.

FIG. 3 is a schematic block diagram of an example of dispersed storage error encoding of data. When a computing device 12 or 16 has data to store it disperse storage error encodes the data in accordance with a dispersed storage error encoding process based on dispersed storage error encoding parameters. The dispersed storage error encoding parameters include an encoding function (e.g., information dispersal algorithm, Reed-Solomon, Cauchy Reed-Solomon, systematic encoding, non-systematic encoding, on-line codes, etc.), a data segmenting protocol (e.g., data segment size, fixed, variable, etc.), and per data segment encoding values. The per data segment encoding values include a total, or pillar width, number (T) of encoded data slices per encoding of a data segment i.e., in a set of encoded data slices); a decode threshold number (D) of encoded data slices of a set of encoded data slices that are needed to recover the data segment; a read threshold number (R) of encoded data slices to indicate a number of encoded data slices per set to be read from storage for decoding of the data segment; and/or a write threshold number (W) to indicate a number of encoded data slices per set that must be accurately stored before the encoded data segment is deemed to have been properly stored. The dispersed storage error encoding parameters may further include slicing information (e.g., the number of encoded data slices that will be created for each data segment) and/or slice security information (e.g., per encoded data slice encryption, compression, integrity checksum, etc.).

In the present example, Cauchy Reed-Solomon has been selected as the encoding function (a generic example is shown in FIG. 4 and a specific example is shown in FIG. 5); the data segmenting protocol is to divide the data object into fixed sized data segments; and the per data segment encoding values include: a pillar width of 5, a decode threshold of 3, a read threshold of 4, and a write threshold of 4. In accordance with the data segmenting protocol, the computing device 12 or 16 divides the data (e.g., a file (e.g., text, video, audio, etc.), a data object, or other data arrangement) into a plurality of fixed sized data segments (e.g., 1 through Y of a fixed size in range of Kilo-bytes to Tera-bytes or more). The number of data segments created is dependent of the size of the data and the data segmenting protocol.

The computing device 12 or 16 then disperse storage error encodes a data segment using the selected encoding function (e.g., Cauchy Reed-Solomon) to produce a set of encoded data slices. FIG. 4 illustrates a generic Cauchy Reed-Solomon encoding function, which includes an encoding matrix (EM), a data matrix (DM), and a coded matrix (CM). The size of the encoding matrix (EM) is dependent on the pillar width number (T) and the decode threshold number (D) of selected per data segment encoding values. To produce the data matrix (DM), the data segment is divided into a plurality of data blocks and the data blocks are arranged into D number of rows with Z data blocks per row. Note that Z is a function of the number of data blocks created from the data segment and the decode threshold number (D). The coded matrix is produced by matrix multiplying the data matrix by the encoding matrix.

FIG. 5 illustrates a specific example of Cauchy Reed-Solomon encoding with a pillar number (T) of five and decode threshold number of three. In this example, a first data segment is divided into twelve data blocks (D1-D12). The coded matrix includes five rows of coded data blocks, where the first row of X11-X14 corresponds to a first encoded data slice (EDS 1_1), the second row of X21-X24 corresponds to a second encoded data slice (EDS 2_1), the third row of X31-X34 corresponds to a third encoded data slice (EDS 3_1), the fourth row of X41-X44 corresponds to a fourth encoded data slice (EDS 4_1), and the fifth row of X51-X54 corresponds to a fifth encoded data slice (EDS 5_1). Note that the second number of the EDS designation corresponds to the data segment number.

Returning to the discussion of FIG. 3, the computing device also creates a slice name (SN) for each encoded data slice (EDS) in the set of encoded data slices. A typical format for a slice name 60 is shown in FIG. 6. As shown, the slice name (SN) 60 includes a pillar number of the encoded data slice (e.g., one of 1-T), a data segment number (e.g., one of 1-Y), a vault identifier (ID), a data object identifier (ID), and may further include revision level information of the encoded data slices. The slice name functions as, at least part of, a DSN address for the encoded data slice for storage and retrieval from the DSN memory 22.

As a result of encoding, the computing device 12 or 16 produces a plurality of sets of encoded data slices, which are provided with their respective slice names to the storage units for storage. As shown, the first set of encoded data slices includes EDS 1_1 through EDS 5_1 and the first set of slice names includes SN 1_1 through SN 5_1 and the last set of encoded data slices includes EDS 1_Y through EDS 5_Y and the last set of slice names includes SN 1_Y through SN 5_Y.

FIG. 7 is a schematic block diagram of an example of dispersed storage error decoding of a data object that was dispersed storage error encoded and stored in the example of FIG. 4. In this example, the computing device 12 or 16 retrieves from the storage units at least the decode threshold number of encoded data slices per data segment. As a specific example, the computing device retrieves a read threshold number of encoded data slices.

To recover a data segment from a decode threshold number of encoded data slices, the computing device uses a decoding function as shown in FIG. 8. As shown, the decoding function is essentially an inverse of the encoding function of FIG. 4. The coded matrix includes a decode threshold number of rows (e.g., three in this example) and the decoding matrix in an inversion of the encoding matrix that includes the corresponding rows of the coded matrix. For example, if the coded matrix includes rows 1, 2, and 4, the encoding matrix is reduced to rows 1, 2, and 4, and then inverted to produce the decoding matrix.

FIG. 9 is a schematic block diagram 900 of an embodiment of a Decentralized, or Distributed, Agreement Protocol (DAP) 80 that may be implemented by a computing device, a storage unit, and/or any other device or unit of the DSN to determine where to store encoded data slices or where to find stored encoded data slices. The DAP 80 includes a plurality of functional rating modules 81. Each of the functional rating modules 81 includes a deterministic function 83, a normalizing function 85, and a scoring function 87.

Each functional rating module 81 receives, as inputs, a slice identifier 82 and storage pool (SP) coefficients (e.g., a first functional rating module 81-1 receives SP 1 coefficients “a” and b). Based on the inputs, where the SP coefficients are different for each functional rating module 81, each functional rating module 81 generates a unique score 93 (e.g., an alpha-numerical value, a numerical value, etc.). The ranking function 84 receives the unique scores 93 and orders them based on an ordering function (e.g., highest to lowest, lowest to highest, alphabetical, etc.) and then selects one as a selected storage pool 86. Note that a storage pool includes one or more sets of storage units 86. Further note that the slice identifier 82 corresponds to a slice name or common attributes of set of slices names. For example, for a set of encoded data slices, the slice identifier 120 specifies a data segment number, a vault ID, and a data object ID, but leaves open ended, the pillar number. As another example, the slice identifier 82 specifies a range of slice names (e.g., 0000 0000 to FFFF FFFF).

As a specific example, the first functional module 81-1 receives the slice identifier 82 and SP coefficients for storage pool 1 of the DSN. The SP coefficients includes a first coefficient (e.g., “a”) and a second coefficient (e.g., “b”). For example, the first coefficient is a unique identifier for the corresponding storage pool (e.g., SP #1's ID for SP 1 coefficient “a”) and the second coefficient is a weighting factor for the storage pool. The weighting factors are derived to ensure, over time, data is stored in the storage pools in a fair and distributed manner based on the capabilities of the storage units within the storage pools.

For example, the weighting factor includes an arbitrary bias which adjusts a proportion of selections to an associated location such that a probability that a source name will be mapped to that location is equal to the location weight divided by a sum of all location weights for all locations of comparison (e.g., locations correspond to storage units). As a specific example, each storage pool is associated with a location weight factor based on storage capacity such that, storage pools with more storage capacity have a higher location weighting factor than storage pools with less storage capacity.

The deterministic function 83, which may be a hashing function, a hash-based message authentication code function, a mask generating function, a cyclic redundancy code function, hashing module of a number of locations, consistent hashing, rendezvous hashing, and/or a sponge function, performs a deterministic function on a combination and/or concatenation (e.g., add, append, interleave) of the slice identifier 82 and the first SP coefficient (e.g., SU 1 coefficient “a”) to produce an interim result 89.

The normalizing function 85 normalizes the interim result 89 to produce a normalized interim result 91. For instance, the normalizing function 85 divides the interim result 89 by a number of possible output permutations of the deterministic function 83 to produce the normalized interim result. For example, if the interim result is 4,325 (decimal) and the number of possible output permutations is 10,000, then the normalized result is 0.4325.

The scoring function 87 performs a mathematical function on the normalized result 91 to produce the score 93. The mathematical function may be division, multiplication, addition, subtraction, a combination thereof, and/or any mathematical operation. For example, the scoring function divides the second SP coefficient (e.g., SP 1 coefficient “b”) by the negative log of the normalized result (e.g., e^(y)=x and/or ln(x)=y). For example, if the second SP coefficient is 17.5 and the negative log of the normalized result is 1.5411 (e.g., e^((0.4235))), the score is 11.3555.

The ranking function 84 receives the scores 93 from each of the function rating modules 81 and orders them to produce a ranking of the storage pools. For example, if the ordering is highest to lowest and there are five storage units in the DSN, the ranking function evaluates the scores for five storage units to place them in a ranked order. From the ranking, the ranking module 84 selects one the storage pools 86, which is the target for a set of encoded data slices.

The DAP 80 may further be used to identify a set of storage units, an individual storage unit, and/or a memory device within the storage unit. To achieve different output results, the coefficients are changed according to the desired location information. The DAP 80 may also output the ranked ordering of the scores.

FIG. 10 is a schematic block diagram 1000 of an example of creating pluralities of sets of slices. Each plurality of sets of encoded data slices (EDSs) corresponds to the encoding of a data object, a portion of a data object, or multiple data object, where a data object is one or more of a file, text, data, digital information, etc. For example, the highlighted plurality of encoded data slices corresponds to a data object having a data identifier of “a2”.

Each encoded data slices of each set of encoded data slices is uniquely identified by its slice name, which is also used as at least part of the DSN address for storing the encoded data slice.

As shown, a set of EDSs includes EDS 1_1_1_a1 through EDS 5_1_1_a1. The EDS number includes pillar number, data segment number, vault ID, and data object ID. Thus, for EDS 1_1_1_a1, it is the first EDS of a first data segment of data object “a1” and is to be stored, or is stored, in vault 1. Note that vaults are a logical memory container supported by the storage units of the DSN. A vault may be allocated to one or more user computing devices.

As is further shown, another plurality of sets of encoded data slices are stored in vault 2 for data object “b1”. There are Y sets of EDSs, where Y corresponds to the number of data segments created by segmenting the data object. The last set of EDSs of data object “b1” includes EDS 1_Y_2_b1 through EDS 5_Y_2_b1. Thus, for EDS 1_Y_2_b1, it is the first EDS of the last data segment “Y” of data object “b1” and is to be stored, or is stored, in vault 2.

FIG. 11 is a schematic block diagram 1100 of an example of storage vaults spanning multiple storage pools. In this example, the DSN memory 22 includes a plurality of storage units 36 arranged into a plurality of storage pools (e.g., 1-n). In this example, each storage pool includes seven storage units for ease of illustration. A storage pool, however, can have many more storage units than seven and, from storage pool to storage pool, may have different numbers of storage units.

The storage pools 1-n support two vaults (vault 1 and vault 2) using only five of seven of the storage units. The number of storage units within a vault correspond to the pillar width number, which is five in this example. Note that a storage pool may have rows of storage units, where SU #1 represents a plurality of storage units, each corresponding to a first pillar number; SU #2 represents a second plurality of storage units, each corresponding to a second pillar number; and so on. Note that other vaults may use more or less than a width of five storage units.

FIG. 12 is a schematic block diagram 1200 of an example of storing pluralities of sets of slices in accordance with the Decentralized, or Distributed, Agreement Protocol (DAP) 80 of FIG. 9. The DAP 80 uses slice identifiers (e.g., the slice name or common elements thereof (e.g., the pillar number, the data segment number, the vault ID, and/or the data object ID)) to identify, for one or more sets of encoded data slices, a set, or pool, of storage units. With respect to the three pluralities of sets of encoded data slices (EDSs) of FIG. 11, the DAP 80 approximately equally distributes the sets of encoded data slices throughout the DSN memory (e.g., among the various storage units).

The first column corresponds to storage units having a designation of SU #1 in their respective storage pool or set of storage units and stores encoded data slices having a pillar number of 1. The second column corresponds to storage units having a designation of SU #2 in their respective storage pool or set of storage units and stores encoded data slices having a pillar number of 2, and so on. Each column of EDSs is divided into one or more groups of EDSs. The delineation of a group of EDSs may correspond to a storage unit, to one or more memory devices within a storage unit, or multiple storage units. Note that the grouping of EDSs allows for bulk addressing, which reduces network traffic.

A range of encoded data slices (EDSs) spans a portion of a group, spans a group, or spans multiple groups. The range may be numerical range of slice names regarding the EDSs, one or more source names (e.g., common aspect shared by multiple slice names), a sequence of slice names, or other slice selection criteria.

FIG. 13 is a schematic block diagram 1300 of an example of adding a storage pool to the DSN. In this example storage pool n+1 is added and is supporting vaults 1 and 2. As result, the Decentralized, or Distributed, Agreement Protocol (DAP) 80 of FIG. 9 is changed to include another functional rating module 81 for the new storage pool and the second coefficients (e.g., “b”, which correspond to the weight factor) are adjusted for some, if not all, of the other functional rating modules 81. As a result of changing the DAP 80, storage responsibility for encoded data slices is going to change, causing them to be transferred between the storage units. When there are significant numbers of encoded data slices to be transferred and there are hundreds to tens of thousands of resources in the DSN (e.g., computing devices, storage units, managing units, integrity units performing rebuilding, etc.), the updating of the DSN is complex and time consuming.

While the DSN is being updated based on the new DAP, data access requests, listing requests, and other types of requests regarding the encoded data slices are still going to be received and need to be processed in a timely manner. Such requests will be based on the old DAP. As such, a request for an encoded data slice (EDS), or information about the EDS, will go to the storage unit identified using the DAP 80 prior to updating it. If the storage unit has already transferred the EDS to the storage unit identified using the new DAP 80, then the storage unit functions as proxy for the new storage unit and the requesting device.

FIG. 14 is a schematic block diagram 1400 of an embodiment of a decentralized, or distributed, agreement protocol (DAP) for generating identified set of storage units in accordance with the present invention. The DAP 80 is similar to the DAP of FIG. 9 but uses a slice identifier 120 instead of a source name 82, uses coefficients for a set of storage units instead of for individual storage units, and the ranking function 84 outputs an identified set of storage units 122 instead of a storage unit ranking 86. The slice identifier 120 corresponds to a slice name or common attributes of set of slices names. For example, for a set of encoded data slices, the slice identifier 120 specifies a data segment number, a vault ID, and a data object ID, but leaves open ended, the pillar number.

In an example of the operation, each of the functional rating modules 81 generates a score 93 for each set of the storage units based on the slice identifier 120. The ranking function 84 orders the scores 93 to produce a ranking. But, instead of outputting the ranking, the ranking function 84 outputs one of the scores, which corresponds to the identified set of storage units.

As can be seen, such a DAP may be implemented and executed for many different applications including for the determination of where to store encoded data slices or where to find stored encoded data slices such as with respect to FIG. 9 as well as the identification of a set of storage units (SUs) such as with respect to FIG. 14. Based on differently provided input to the DAP, differently provided information may be output. Generally speaking, the more detailed information is that is provided to the DAP, then the more detailed information will be output when from the DAP when executed.

A dispersed or distributed storage network (DSN) module includes a plurality of distributed storage and/or task (DST) execution units 36 (e.g., storage units (SUs), computing devices, etc.) that may be located at geographically different sites (e.g., one in Chicago, one in Milwaukee, etc.). Each of the DST execution units is operable to store dispersed error encoded data and/or to execute, in a distributed manner, one or more tasks on data. The tasks may be a simple function (e.g., a mathematical function, a logic function, an identify function, a find function, a search engine function, a replace function, etc.), a complex function (e.g., compression, human and/or computer language translation, text-to-voice conversion, voice-to-text conversion, etc.), multiple simple and/or complex functions, one or more algorithms, one or more applications, etc.

FIG. 15 is a schematic block diagram of another embodiment of a dispersed or distributed storage network (DSN) that includes a migration agent module 1510, the network 24 of FIG. 1, and at least two storage unit (SU) pools 1-2, etc. The migration agent module 1510 includes a Decentralized, or Distributed, Agreement Protocol (DAP) module 1512 such as may be implemented as described above and the DS client module 34 of FIG. 1. The migration agent module 1510 may be included in, be, or be part of a computing device such as computing device 12 or 16. Each SU pool includes a set of SUs 1-n. Each SU may be implemented utilizing the SU 36 of FIG. 1. Hereafter, each SU may be referred to interchangeably as a storage unit and each SU pool may be referred to interchangeably as a storage unit pool. The DSN functions to pace migration of encoded data slices (EDSs) from a storage pool to another storage pool.

In an example of operation of the pacing of the migration of the EDSs, the migration agent module 1510 determines to migrate the EDSs from the storage pool to the other storage pool. The determining includes at least one of detecting storage unit retirement, detecting a storage unit replacement, detecting new storage resources, detecting new location weights of a Decentralized, or Distributed, Agreement Protocol (DAP) function associated with storage units and/or with one or more storage pools, interpreting a request, and interpreting a slice migration schedule.

Having determined to migrate EDSs, the migration agent module 1510 identifies storage resources associated with the EDSs for migration. The identifying includes at least one of obtaining slice names of the EDSs for migration, performing a lookup of storage resource identifiers associated with the obtains slice names to identify source locations for the EDSs for migration, and performing a DAP function on the slice names utilizing location weights for associated storage resources to identify the destination locations for the EDSs for migration. For example, the DS client module 34 issues a ranked scoring information request 1530 to the DAP module 1510, where the request includes a slice name for EDS of the first storage pool for migration, receives ranked scoring information 1520 from the DAP module 1512, and identifies the second storage pool as the destination resource based on a highest score of the ranked scoring information 1520.

Having identified the storage resources, the migration agent module 1510 obtains performance information 1550 associated with the identified storage resources (e.g., the performance information 1550 may be viewed as obtaining from both the SU pool 1 and the SU pool 2 as performance information 1552 and performance information 1554, such that each of the performance information 1552 and performance information 1554 include different respective information about the SU pool 1 and the SU pool 2 and cooperatively include the performance information 1550 that gets communicated to the migration agent module 1510). The performance information includes one or more of slice access latency level (e.g., retrieval delay, storage time frame), slice access capacity level (e.g., bandwidth), a network resource availability level, and a storage resource availability level. The obtaining includes at least one of interpreting a query response, interpreting an error message, receiving the performance information from the identified storage resources, initiating a test, and interpreting a test result. For example, the DS client module 34 receives, via the network 24, the performance information from the SUs of the SU pools 1 and 2.

Having obtained the performance information, the migration agent module 1510 generates a migration schedule 1540 for the EDSs for migration based on the performance information. The migration schedule 1540 includes one or more of slice names of the slices for migration, a desired time of migration completion, a migration pacing factor (e.g., a target migration rate, a migration aggressiveness level), an expected slice access loading level profile (e.g., a user device access rate, the rebuilding rate), and a maximum impact level (e.g., a degradation of slice access performance, a lowest threshold level of slice access performance). The generating includes one or more of identifying a portion of slice names of the EDSs for migration and identifying a time frame of the migration for the identified portion based on at least a portion of the performance information (e.g., generate a migration pacing factor based on a desired time frame of completion of the migration and the performance information).

Having generated the migration schedule 1540, the migration agent module 1510 sends the migration schedule 1540 (e.g., which may be viewed as being sent to both the SU pool 1 and the SU pool 2 as migration schedule 1542 and migration schedule 1544, and both the migration schedule 1542 and migration schedule 1544 include same or similar information as the migration schedule 1542 and migration schedule 1540 in some examples) to the identified storage resources to facilitate the migration of the EDSs for migration. For example, the DS client module 34 sends, via the network 24, the migration scheduled to the SUs of the first and second storage pools. Having received the migration schedule, the identified storage resources perform the migration. For example, the storage units of the first storage pool send, via the network 24, migration slices 1560 to the second storage pool (e.g., migration slices 1562, which may be the migration slices 1560 and/or be modified such as to include additional information after having been transmitted via the network 24) for storage in accordance with the migration schedule 1540.

Prior to completion of the migration, the migration agent module 1510 obtains updated performance information. Having obtained the updated performance information, the migration agent module 1510 updates the migration schedule 1540 to produce an updated migration schedule when the updated performance information compares unfavorably to a desired performance information level. The updating includes one or more of detecting the unfavorable conditions (e.g., storage resource availability level is less than a desired minimum storage resource availability level, slice access performance level has degraded beyond a degradation threshold level, etc.; and adjusting the migration pacing factor to produce the updated migration schedule. When updating the performance information, the migration agent module 1510 sends, via the network 24, the updated migration schedule to the identified storage resources.

In an example of operation and implementation, a computing device (e.g., the migration agent module 1530, computing device 12 or 16) includes an interface configured to interface and communicate with a dispersed or distributed storage network (DSN), a memory that stores operational instructions, and a processing module operably coupled to the interface and to the memory. The processing module, when operable within the computing device based on the operational instructions, is configured to perform various operations.

In an example, the computing device is configured to determine to facilitate migration of a plurality of encoded data slices (EDSs) from a first storage unit (SU) pool to a second SU pool, wherein a data object is segmented into a plurality of data segments. A data segment of the plurality of data segments is dispersed error encoded in accordance with dispersed error encoding parameters to produce a set of EDSs that includes at least one of the plurality of EDSs. The computing device is also configured to identify storage resources associated with the plurality of EDSs to be migrated. The computing device is also configured to generate a migration schedule for the plurality of EDSs based on performance information associated with storage resources associated with the plurality of EDSs to be migrated. The computing device is also configured to facilitate the migration of the plurality of EDSs based on the migration schedule using the storage resources based on a first aggression factor, wherein the first aggression factor corresponds to an acceptable level of impact to non-migration traffic within the DSN.

During and prior to completion of the migration of the plurality of EDSs based on the migration schedule, the computing device is configured to obtain performance information regarding the migration of the plurality of EDSs based on the migration schedule. When the performance information includes impact information that compares unfavorably with an aggression factor threshold, the computing device is configured to modify the first aggression factor to generate a second aggression factor. The computing device is also configured to continue to facilitate the migration of the plurality of EDSs based on the migration schedule using the storage resources based on second aggression factor, wherein the aggression factor threshold corresponds to a maximum degree of tolerable acceptable level of impact to the non-migration traffic within the DSN.

In some examples, when the performance information includes migration rate information that compares unfavorably with a migration rate threshold, the computing device is configured to modify the migration schedule to generate another migration schedule and continue to facilitate the migration of the plurality of EDSs based on the other migration schedule, wherein the migration rate threshold corresponds to an acceptable migration rate to effectuate migration of the plurality of EDSs based on the migration schedule.

In even other examples, during and prior to the completion of the migration of the plurality of EDSs based on the migration schedule, the computing device is configured to obtain the performance information includes DSN resource availability information regarding the migration of the plurality of EDSs based on the migration schedule. When the DSN resource availability information compares unfavorably with a DSN resource availability information threshold, the computing device is configured to increase a migration rate of the migration of the plurality of EDSs based on the migration schedule. Alternatively, when the DSN resource availability information compares favorably with the DSN resource availability information threshold, the computing device is configured to decrease or maintain the migration rate of the migration of the plurality of EDSs based on the migration schedule.

In yet other examples, the computing device is configured to determine to facilitate the migration of the plurality of EDSs from the first SU pool to the second SU pool based on any one or more or combination of a SU retirement, detection of a SU replacement, detection of new storage resources, detection of new location weights of a Decentralized, or Distributed, Agreement Protocol (DAP) function associated with SU of the at least one of the first SU or the second SU pool, interpretation of a request received from another computing device, and/or interpretation of another migration schedule.

With respect to the set of EDSs associated with the data segment, note that the set of EDSs is of pillar width, and the set of EDSs are distributedly stored among a plurality of SUs. This plurality of SUs may include at least one SU within the SU pool 1 and/or the SU pool 2. Note also that a decode threshold number of EDSs are needed to recover the data segment, and a read threshold number of EDSs provides for reconstruction of the data segment. Also, a write threshold number of EDSs provides for a successful transfer of the set of EDSs from a first at least one location in the DSN to a second at least one location in the DSN.

Note that the computing device may be implemented and located in any desired location within the DSN including being located at a first premises that is remotely located from at least one SU of the first SU pool or the second SU pool within the DSN. Also, note that the computing device may be implemented as any of a variety of types of devices including a SU of the first SU pool or the second SU pool within the DSN, a wireless smart phone, a laptop, a tablet, a personal computers (PC), a work station, and/or a video game device. Note also that the dispersed or distributed storage network (DSN) may be implemented in various ways and may include any one or more of a wireless communication system, a wire lined communication systems, a non-public intranet system, a public internet system, a local area network (LAN), and/or a wide area network (WAN).

FIG. 16 is a flowchart illustrating an example of pacing migration of encoded data slices (EDS). The method 1600 begins or continues at a step 1610 where a processing module (e.g., of a migration agent module) determines to facilitate migration of EDSs from one or more storage resources to one or more other storage resources. The determining includes one or more of detecting a storage unit retirement and/or replacement, detecting provisioning of a new storage unit, detecting new location weights, receiving a request, identifying source storage resources by performing a lookup, and identifying destination storage resources by performing a Decentralized, or Distributed, Agreement Protocol (DAP) function on the slice names.

The method 1600 continues at the step 1620 where the processing module obtains performance information associated with the storage resources of the migration. The obtaining includes at least one of receiving the performance information from the storage resources, interpreting a test result, and interpreting a query response.

The method 1600 continues at the step 1630 where the processing module generates a migration schedule for the EDSs for migration based on the performance information. For example, the processing module assigns a migration pacing factor to a portion of the slices for migration based on a time frame of migration and performance information.

The method 1600 continues at the step 1640 where the processing module sends the migration scheduled to the storage resources of the migration. For example, the processing module transmits the migration schedule to at least some storage resources of the storage resources of the migration, where the storage resources utilize the migration schedule when performing one or more steps of the migration of the EDSs.

The method 1600 continues at the step 1650 where the processing module obtains updated performance information while the slice migration is active. For example, the processing module issues a performance information request and receives the updated performance information.

The method 1600 continues at the step 1660 where the processing module updates the migration schedule when the updated performance information compares unfavorably to a desired performance level. For example, the processing module detects unfavorable execution of the migration of the EDSs (e.g., a slice access performance level has degraded beyond a degradation threshold level, etc.) and updates the migration pacing factor. The method 1600 continues at the step 1670 of the processing module sends the updated migration scheduled to the storage resources of the migration. For example, the processing module transmits the updated migration scheduled to at least some storage resources of the storage resources of the migration, where the storage resources utilize the updated migration schedule when performing further steps of the migration of the EDSs (e.g., slowing down sending of the further slices of the migration).

FIG. 17 is a diagram illustrating an embodiment of a method 1700 for execution by one or more computing devices in accordance with the present invention. The method 1700 operates in step 1710 by determining to facilitate migration of a plurality of encoded data slices (EDSs) from a first storage unit (SU) pool to a second SU pool within a dispersed or distributed storage network (DSN), wherein a data object is segmented into a plurality of data segments. Note that a data segment of the plurality of data segments is dispersed error encoded in accordance with dispersed error encoding parameters to produce a set of EDSs that includes that includes at least one of the plurality of EDSs. The method 1700 continues in step 1720 by identifying storage resources associated with the plurality of EDSs to be migrated.

The method 1700 then operates in step 1730 by generating a migration schedule for the plurality of EDSs based on performance information associated with storage resources associated with the plurality of EDSs to be migrated. The method 1700 continues in step 1740 by facilitating (e.g., via an interface of the computing device configured to interface and communicate with the DSN) the migration of the plurality of EDSs based on the migration schedule using the storage resources based on a first aggression factor, wherein the first aggression factor corresponds to an acceptable level of impact to non-migration traffic within the DSN.

During and prior to completion of the migration of the plurality of EDSs based on the migration schedule, the method 1700 continues in step 1750 by obtaining (e.g., via the interface of the computing device) performance information regarding the migration of the plurality of EDSs based on the migration schedule.

The method 1700 then operates in step 1760 by determining whether the performance information includes impact information that compares unfavorably with an aggression factor threshold. When the performance information includes impact information that compares favorably with an aggression factor threshold as determined in step 1770, the method 1700 ends or loops back to step 1750.

Alternatively, when the performance information includes impact information that compares unfavorably with an aggression factor threshold as determined in step 1770, the method 1700 then operates in step 1780 by modifying the first aggression factor to generate a second aggression factor. The method 1700 continues in step 1790 by continuing to facilitate the migration of the plurality of EDSs based on the migration schedule using the storage resources based on second aggression factor, wherein the aggression factor threshold corresponds to a maximum degree of tolerable acceptable level of impact to the non-migration traffic within the DSN.

In some examples and certain variants of the method 1700, when the performance information includes migration rate information that compares unfavorably with a migration rate threshold, a variant of the method 1700 operates by modifying the migration schedule to generate another migration schedule. The method 1700 continues by continuing to facilitate (e.g., via the interface of the computing device) the migration of the plurality of EDSs based on the other migration schedule, wherein the migration rate threshold corresponds to an acceptable migration rate to effectuate migration of the plurality of EDSs based on the migration schedule.

In some other examples and certain other variants of the method 1700, during and prior to the completion of the migration of the plurality of EDSs based on the migration schedule, the method 1700 operates by obtaining the performance information includes DSN resource availability information regarding the migration of the plurality of EDSs based on the migration schedule. When the DSN resource availability information compares unfavorably with a DSN resource availability information threshold, another variant of the method 1700 operates by increasing a migration rate of the migration of the plurality of EDSs based on the migration schedule. When the DSN resource availability information compares favorably with the DSN resource availability information threshold, another variant of the method 1700 operates by decreasing or maintaining the migration rate of the migration of the plurality of EDSs based on the migration schedule.

In even other examples and certain other variants of the method 1700, yet another variant of the method 1700 operates by determining to facilitate the migration of the plurality of EDSs from the first SU pool to the second SU pool based on one or more of detection of a SU retirement, detection of a SU replacement, detection of new storage resources, detection of new location weights of a Decentralized, or Distributed, Agreement Protocol (DAP) function associated with SU of the first SU pool and/or the second SU pool, interpretation of a request received from another computing device, and/or interpretation of another migration schedule.

This disclosure presents, among other things, various examples of migration of encoded data slices (EDSs) within a dispersed or distributed storage network (DSN). In many cases, a DSN memory may require a period of high load caused by migration-related traffic. This can occur in many situations, including any one or more or combination of when adding storage resources to a DSN memory, removing storage resources from a DSN memory, retiring or replacing storage resources to a DSN memory, and replacing storage units (SUs) in a DSN memory. In some examples, these events are scheduled such that they happen at regular time intervals, and thus the time it may take to complete is flexible so long as it fits into the schedule of future operations. For this reason, in some examples, the migration-related traffic is generally a lower priority than less time-sensitive operations, such as requested input/output (I/O) and rebuilding related traffic. In such cases migration should be conducted in a manner that minimizes disruption to the system while nonetheless completing as fast as possible while preventing such a disruption. When an action is taken that will result in migration-related load, a schedule may be defined using any of a variety of parameters including desired time of completion of the migration, periods of high client/rebuild load (when little or no excess network/storage resources are available), periods of reduced client/rebuild load (when ample excess network/storage resources are available), a default “aggression factor” that indicates a tolerable level of impact to client/rebuild operations (e.g., as a parameter in a Multi-Armed-Bandits algorithm, or similar), and/or an aggression factor threshold that may be representative of the maximum degree of tolerable disruption to client/rebuilder operations.

Agents participating in the migration (e.g., SUs which apply a Decentralized, or Distributed, Agreement Protocol (DAP) to determine what data needs to move, and where, etc.) utilize the above scheduling information to determine the degree to which to throttle their migration-related traffic. If, in the analysis of past migration rate (over some previous time window) the migration agents determine that the rate is insufficient to meet the scheduled deadline for the completion of the migration, they may indicate an error or increase their aggression factor, if on the other hand, they determine that the migration will complete well ahead of schedule, they may decrease their aggression factor to cause less disruption while still meeting the deadline. If the aggression factor would have to be increased beyond the aggression factor threshold, in order to meet the deadline then an error will be generating, which indicates that either the aggression factor threshold must be increased, or that the desired date of migration completion will be missed.

It is noted that terminologies as may be used herein such as bit stream, stream, signal sequence, etc. (or their equivalents) have been used interchangeably to describe digital information whose content corresponds to any of a number of desired types (e.g., data, video, speech, audio, etc. any of which may generally be referred to as ‘data’).

As may be used herein, the terms “substantially” and “approximately” provides an industry-accepted tolerance for its corresponding term and/or relativity between items. Such an industry-accepted tolerance ranges from less than one percent to fifty percent and corresponds to, but is not limited to, component values, integrated circuit process variations, temperature variations, rise and fall times, and/or thermal noise. Such relativity between items ranges from a difference of a few percent to magnitude differences. As may also be used herein, the term(s) “configured to”, “operably coupled to”, “coupled to”, and/or “coupling” includes direct coupling between items and/or indirect coupling between items via an intervening item (e.g., an item includes, but is not limited to, a component, an element, a circuit, and/or a module) where, for an example of indirect coupling, the intervening item does not modify the information of a signal but may adjust its current level, voltage level, and/or power level. As may further be used herein, inferred coupling (i.e., where one element is coupled to another element by inference) includes direct and indirect coupling between two items in the same manner as “coupled to”. As may even further be used herein, the term “configured to”, “operable to”, “coupled to”, or “operably coupled to” indicates that an item includes one or more of power connections, input(s), output(s), etc., to perform, when activated, one or more its corresponding functions and may further include inferred coupling to one or more other items. As may still further be used herein, the term “associated with”, includes direct and/or indirect coupling of separate items and/or one item being embedded within another item.

As may be used herein, the term “compares favorably”, indicates that a comparison between two or more items, signals, etc., provides a desired relationship. For example, when the desired relationship is that signal 1 has a greater magnitude than signal 2, a favorable comparison may be achieved when the magnitude of signal 1 is greater than that of signal 2 or when the magnitude of signal 2 is less than that of signal 1. As may be used herein, the term “compares unfavorably”, indicates that a comparison between two or more items, signals, etc., fails to provide the desired relationship.

As may also be used herein, the terms “processing module”, “processing circuit”, “processor”, and/or “processing unit” may be a single processing device or a plurality of processing devices. Such a processing device may be a microprocessor, micro-controller, digital signal processor, microcomputer, central processing unit, field programmable gate array, programmable logic device, state machine, logic circuitry, analog circuitry, digital circuitry, and/or any device that manipulates signals (analog and/or digital) based on hard coding of the circuitry and/or operational instructions. The processing module, module, processing circuit, and/or processing unit may be, or further include, memory and/or an integrated memory element, which may be a single memory device, a plurality of memory devices, and/or embedded circuitry of another processing module, module, processing circuit, and/or processing unit. Such a memory device may be a read-only memory, random access memory, volatile memory, non-volatile memory, static memory, dynamic memory, flash memory, cache memory, and/or any device that stores digital information. Note that if the processing module, module, processing circuit, and/or processing unit includes more than one processing device, the processing devices may be centrally located (e.g., directly coupled together via a wired and/or wireless bus structure) or may be distributedly located (e.g., cloud computing via indirect coupling via a local area network and/or a wide area network). Further note that if the processing module, module, processing circuit, and/or processing unit implements one or more of its functions via a state machine, analog circuitry, digital circuitry, and/or logic circuitry, the memory and/or memory element storing the corresponding operational instructions may be embedded within, or external to, the circuitry comprising the state machine, analog circuitry, digital circuitry, and/or logic circuitry. Still further note that, the memory element may store, and the processing module, module, processing circuit, and/or processing unit executes, hard coded and/or operational instructions corresponding to at least some of the steps and/or functions illustrated in one or more of the figures. Such a memory device or memory element can be included in an article of manufacture.

One or more embodiments have been described above with the aid of method steps illustrating the performance of specified functions and relationships thereof. The boundaries and sequence of these functional building blocks and method steps have been arbitrarily defined herein for convenience of description. Alternate boundaries and sequences can be defined so long as the specified functions and relationships are appropriately performed. Any such alternate boundaries or sequences are thus within the scope and spirit of the claims. Further, the boundaries of these functional building blocks have been arbitrarily defined for convenience of description. Alternate boundaries could be defined as long as the certain significant functions are appropriately performed. Similarly, flow diagram blocks may also have been arbitrarily defined herein to illustrate certain significant functionality.

To the extent used, the flow diagram block boundaries and sequence could have been defined otherwise and still perform the certain significant functionality. Such alternate definitions of both functional building blocks and flow diagram blocks and sequences are thus within the scope and spirit of the claims. One of average skill in the art will also recognize that the functional building blocks, and other illustrative blocks, modules and components herein, can be implemented as illustrated or by discrete components, application specific integrated circuits, processors executing appropriate software and the like or any combination thereof.

In addition, a flow diagram may include a “start” and/or “continue” indication. The “start” and “continue” indications reflect that the steps presented can optionally be incorporated in or otherwise used in conjunction with other routines. In this context, “start” indicates the beginning of the first step presented and may be preceded by other activities not specifically shown. Further, the “continue” indication reflects that the steps presented may be performed multiple times and/or may be succeeded by other activities not specifically shown. Further, while a flow diagram indicates a particular ordering of steps, other orderings are likewise possible provided that the principles of causality are maintained.

The one or more embodiments are used herein to illustrate one or more aspects, one or more features, one or more concepts, and/or one or more examples. A physical embodiment of an apparatus, an article of manufacture, a machine, and/or of a process may include one or more of the aspects, features, concepts, examples, etc. described with reference to one or more of the embodiments discussed herein. Further, from figure to figure, the embodiments may incorporate the same or similarly named functions, steps, modules, etc. that may use the same or different reference numbers and, as such, the functions, steps, modules, etc. may be the same or similar functions, steps, modules, etc. or different ones.

Unless specifically stated to the contra, signals to, from, and/or between elements in a figure of any of the figures presented herein may be analog or digital, continuous time or discrete time, and single-ended or differential. For instance, if a signal path is shown as a single-ended path, it also represents a differential signal path. Similarly, if a signal path is shown as a differential path, it also represents a single-ended signal path. While one or more particular architectures are described herein, other architectures can likewise be implemented that use one or more data buses not expressly shown, direct connectivity between elements, and/or indirect coupling between other elements as recognized by one of average skill in the art.

The term “module” is used in the description of one or more of the embodiments. A module implements one or more functions via a device such as a processor or other processing device or other hardware that may include or operate in association with a memory that stores operational instructions. A module may operate independently and/or in conjunction with software and/or firmware. As also used herein, a module may contain one or more sub-modules, each of which may be one or more modules.

As may further be used herein, a computer readable memory includes one or more memory elements. A memory element may be a separate memory device, multiple memory devices, or a set of memory locations within a memory device. Such a memory device may be a read-only memory, random access memory, volatile memory, non-volatile memory, static memory, dynamic memory, flash memory, cache memory, and/or any device that stores digital information. The memory device may be in a form a solid state memory, a hard drive memory, cloud memory, thumb drive, server memory, computing device memory, and/or other physical medium for storing digital information.

While particular combinations of various functions and features of the one or more embodiments have been expressly described herein, other combinations of these features and functions are likewise possible. The present disclosure is not limited by the particular examples disclosed herein and expressly incorporates these other combinations. 

What is claimed is:
 1. A storage unit (SU) comprising: an interface configured to interface and communicate with a distributed storage network (DSN); memory that stores operational instructions; and processing circuitry operably coupled to the interface and to the memory, wherein the processing circuitry is configured to execute the operational instructions to: in accordance with migration of a plurality of encoded data slices (EDSs) from a first storage unit (SU) pool that includes the SU to a second SU pool that includes another SU within the DSN based on a migration schedule that is based on storage resources associated with the plurality of EDSs to be migrated and based on a first aggression factor, transmit a first EDS that is stored within the SU via the interface and via the DSN to the another SU in accordance with the first aggression factor, wherein a data object is segmented into a plurality of data segments, wherein a data segment of the plurality of data segments is dispersed error encoded in accordance with dispersed error encoding parameters to produce a set of EDSs that includes at least one of the plurality of EDSs; and based on adaptation of the migration of the plurality of EDSs from the first aggression factor to a second aggression factor during and prior to completion of the migration of the plurality of EDSs, transmit a second EDS that is stored within the SU via the interface and via the DSN to the another SU in accordance with the second aggression factor.
 2. The SU of claim 1, wherein: adaptation of the migration of the plurality of EDSs from the first aggression factor to the second aggression factor during and prior to completion of the migration of the plurality of EDSs is based on a determination that performance information regarding the migration of the plurality of EDSs compares unfavorably with an aggression factor threshold; the first aggression factor corresponds to an acceptable level of impact to non-migration traffic within the DSN; and the aggression factor threshold corresponds to a maximum degree of tolerable acceptable level of impact to the non-migration traffic within the DSN.
 3. The SU of claim 1, wherein the processing circuitry is further configured to execute the operational instructions to: transmit, via the interface and to a computing device within the DSN, information corresponding to performance of the SU to be used by the computing device in accordance with obtaining performance information that includes DSN resource availability information regarding the migration of the plurality of EDSs based on the migration schedule.
 4. The SU of claim 1, wherein a computing device in the DSN is configured to determine to facilitate the migration of the plurality of EDSs from the first SU pool to the second SU pool based on at least one of detection of a storage unit (SU) retirement, detection of a SU replacement, detection of new storage resources, detection of new location weights of a Decentralized, or Distributed, Agreement Protocol (DAP) function associated with an SU of the at least one of the first SU pool or the second SU pool, interpretation of a request received from another computing device, or interpretation of another migration schedule.
 5. The SU of claim 4, wherein the computing device is further configured to: during and prior to the completion of the migration of the plurality of EDSs based on the migration schedule, obtain performance information that includes DSN resource availability information regarding the migration of the plurality of EDSs based on the migration schedule; based on a first other determination that the DSN resource availability information compares unfavorably with a DSN resource availability information threshold, increase a migration rate of the migration of the plurality of EDSs based on the migration schedule; and based on a second other determination that the DSN resource availability information compares favorably with the DSN resource availability information threshold, decrease or maintain the migration rate of the migration of the plurality of EDSs based on the migration schedule.
 6. The SU of claim 1, wherein: the set of EDSs is of pillar width; the set of EDSs are distributedly stored among a plurality of SUs; a decode threshold number of EDSs are needed to recover the data segment; a read threshold number of EDSs provides for reconstruction of the data segment; and a write threshold number of EDSs provides for a successful transfer of the set of EDSs from a first at least one location in the DSN to a second at least one location in the DSN.
 7. The SU of claim 1, wherein the processing circuitry is further configured to execute the operational instructions to: receive, via the interface and from a computing device within the DSN, at least one of the migration schedule, the first aggression factor, or the second aggression factor.
 8. The SU of claim 7, wherein the computing device includes another SU of the set of SUs within the DSN, a wireless smart phone, a laptop, a tablet, a personal computers (PC), a work station, or a video game device.
 9. The SU of claim 1, wherein the SU is located at a first premises that is remotely located from a second premises of at least one other SU of the first SU pool or the second SU pool within the DSN.
 10. The SU of claim 1, wherein the DSN includes at least one of a wireless communication system, a wire lined communication system, a non-public intranet system, a public internet system, a local area network (LAN), or a wide area network (WAN).
 11. A method for execution by a storage unit (SU), the method comprising: in accordance with migration of a plurality of encoded data slices (EDSs) from a first storage unit (SU) pool that includes the SU to a second SU pool that includes another SU within a distributed storage network (DSN) based on a migration schedule that is based on storage resources associated with the plurality of EDSs to be migrated and based on a first aggression factor, transmit a first EDS that is stored within the SU via an interface of the SU that is configured to interface and communicate with the DSN and via the DSN to the another SU in accordance with the first aggression factor, wherein a data object is segmented into a plurality of data segments, wherein a data segment of the plurality of data segments is dispersed error encoded in accordance with dispersed error encoding parameters to produce a set of EDSs that includes at least one of the plurality of EDSs; and based on adaptation of the migration of the plurality of EDSs from the first aggression factor to a second aggression factor during and prior to completion of the migration of the plurality of EDSs, transmit a second EDS that is stored within the SU via the interface and via the DSN to the another SU in accordance with the second aggression factor.
 12. The method of claim 11, wherein: adaptation of the migration of the plurality of EDSs from the first aggression factor to the second aggression factor during and prior to completion of the migration of the plurality of EDSs is based on a determination that performance information regarding the migration of the plurality of EDSs compares unfavorably with an aggression factor threshold; the first aggression factor corresponds to an acceptable level of impact to non-migration traffic within the DSN; and the aggression factor threshold corresponds to a maximum degree of tolerable acceptable level of impact to the non-migration traffic within the DSN.
 13. The method of claim 11 further comprising: transmitting, via the interface and to a computing device within the DSN, information corresponding to performance of the SU to be used by the computing device in accordance with obtaining performance information that includes DSN resource availability information regarding the migration of the plurality of EDSs based on the migration schedule.
 14. The method of claim 11 further comprising: operating a computing device in the DSN to determine to facilitate the migration of the plurality of EDSs from the first SU pool to the second SU pool based on at least one of detection of a storage unit (SU) retirement, detection of a SU replacement, detection of new storage resources, detection of new location weights of a Decentralized, or Distributed, Agreement Protocol (DAP) function associated with an SU of the at least one of the first SU pool or the second SU pool, interpretation of a request received from another computing device, or interpretation of another migration schedule.
 15. The method of claim 14 further comprising operating the computing device in the DSN for: during and prior to the completion of the migration of the plurality of EDSs based on the migration schedule, obtaining performance information that includes DSN resource availability information regarding the migration of the plurality of EDSs based on the migration schedule; based on a first other determination that the DSN resource availability information compares unfavorably with a DSN resource availability information threshold, increasing a migration rate of the migration of the plurality of EDSs based on the migration schedule; and based on a second other determination that the DSN resource availability information compares favorably with the DSN resource availability information threshold, decreasing or maintaining the migration rate of the migration of the plurality of EDSs based on the migration schedule.
 16. The method of claim 11, wherein: the set of EDSs is of pillar width; the set of EDSs are distributedly stored among a plurality of SUs; a decode threshold number of EDSs are needed to recover the data segment; a read threshold number of EDSs provides for reconstruction of the data segment; and a write threshold number of EDSs provides for a successful transfer of the set of EDSs from a first at least one location in the DSN to a second at least one location in the DSN.
 17. The method of claim 11 further comprising: receiving, via the interface and from a computing device within the DSN, at least one of the migration schedule, the first aggression factor, or the second aggression factor.
 18. The method of claim 17, wherein the computing device includes another SU of the set of SUs within the DSN, a wireless smart phone, a laptop, a tablet, a personal computers (PC), a work station, or a video game device.
 19. The method of claim 11, wherein the SU is located at a first premises that is remotely located from a second premises of at least one other SU of the first SU pool or the second SU pool within the DSN.
 20. The method of claim 11, wherein the DSN includes at least one of a wireless communication system, a wire lined communication system, a non-public intranet system, a public internet system, a local area network (LAN), or a wide area network (WAN). 